MXPA00009253A - Bone tissue regenerating composition - Google Patents

Abstract

The invention relates to a composition for regenerating bone tissue and a method for preparing said composition, which is usedchiefly but no exclusively in oral surgery and consists of a gel rich in plasma growth factors (PRGF gel) obtained from the blood of the patient. With the aid of said gel, quicker and more effective bone regeneration of the cavities to be treated is obtained in comparison with known materials and techniques.

Description

Reqenerator of bone tissue The invention relates to the regeneration of bone tissue within the surgical technique in general, and more particularly in the technique of oral surgery, in which the filling of a bone cavity is carried out with a graft material that stimulates and accelerates the cited regeneration.

Up to the present time, various graft materials have been used, the nature of which determines the shape and manner in which the bone regeneration takes place.

Thus, several authors have published studies and reports on the use of different materials and / or compounds for this purpose.

Yarnaza i Y, Oida S, Akimoto Y, Shioda S in Clin Orthop Related Res 1988; 2. 3. 4; 240-9, refer to the use of a morphogenetic protein from bone for said regeneration, associated in a composition with Paris plaster (calcium sulfate).

Both autologous bone and demineralized bone "DFDBA" have been traditionally applied in this technique, alone or combined with other elements, so that they have constituted bone cavity filling grafts.

Likewise, such a filling material has also been protected with various barrier materials in order to prevent the advance of adjacent fabrics on said filling material. As barrier materials for said filling material several have been used, highlighting among them the most popular one, the polytetrafluoroethylene in membranes, despite, however, generating problems derived from the fact that it is not biodegradable and can cause infections in certain cases. In addition, when used in solid form, it must be worked during the treatment and then sutured in its ideal position.

For the US No. 5,366,507 a composition is known, which combines a filler material based on a mixture of demineralized bone and calcium sulfate and a barrier material consisting of calcium sulfate. This composition does not greatly improve upon the prior techniques.

It is known from numerous studies that the growth factors contained in the blood favor the formation of bone, particularly the growth factors P.D.G.F. and T.G.F.ß However, the obtaining or concentration of these rich factors on an outpatient basis is not known, nor the effect thereof in a way that can be measured or observed clinically.

It is an object of the invention, the use of a plasma gel rich in growth factors P.R.G.F as a graft material for the filling and regeneration of bone in cavities or bone defects or for regeneration.

Another object of the invention is the method for obtaining and preparing rich plasma on an outpatient basis.

It is an object of the invention a method and a composition for the regeneration of bone tissue that provides a greater speed in said regeneration and that is rapid in its implantation in the patient.

Another object of the invention is the configuration of a unit or kit for the preparation of the plasma gel rich in P.R.G.F.

Selling the use of plasma gel rich in growth factors P.R.G.F. for the regeneration of the bone tissue, it provides an acceleration and favoring of the said bone regeneration that is greater than with the application of the techniques in use at present, as well as a more rapid and predictable healing of the soft tissues, such and as will be appreciated later when considering the results obtained.

For the preparation of said gel, according to the invention, the first step is to extract blood from the patients themselves, minutes before the start of surgery and prior to the administration of anesthesia. From 10 to 40 ml. were extracted from each patient, using 5 ml tubes. in which 10% of trisodium citrate was placed as an anticoagulant.

The tubes were centrifuged at speeds between 150 and 800 G, according to different protocols that can be applied, for about 6 minutes or less, depending on the speed, at room temperature, separating the blood into three basic or constituent components, namely: Red blood cells at the bottom of the tube - Plasma rich in growth factors P.R.G.F. in the center of the tube, above the red fraction.

- Plasma poor in growth factors P.P.G.F. on top of the tube.

A portion, Iml. of the upper phase P.P.G.F. of each tube of 5 ml. It was discarded. The platelets present in said P.P.G.F. they were less than 15%, as measured by count n = 10.

The rich plasma was taken from the central zone of the tubes and transferred to Eppendorf tubes, adding 50 μl of 10% calcium chloride to each tube containing 1.2 ml of the aforementioned PRGF, so that keeping this plasma well, after from a time lapse of 15 to 25 minutes the PRGF gel was formed This plasma can also be mixed with human thrombin, 500 units, plus calcium chloride and thus obtain the gel instantaneously (from 3 to 10 sec.) And even be able to apply it with a syringe.

The gel was used only for the filling of bone cavities to be regenerated with optimal results, or with the help of a conventional outer covering barrier material, as will be discussed later.

The gel can be combined with other components, such as calcium sulfate, autologous bone, resorbable hydroxyapatite, tricalcium phosphate, calcium carbonate or other reagent, osteoinductive or osteoconductive materials.

For the production of the plasma gel rich in P.R.G.F., the preparation unit or kit will contain a centrifuge, pipettes for the separation of the plasma fractions and a blood extraction system.

The selection of patients was based on the absence of local or systematic diseases that could contraindicate the treatment. Consent was obtained informing all patients who entered the study. These were 20 patients in whom an extraction was indicated by a vertical fracture or advanced periodontal disease and to whom implants were placed in such a way that a biopsy of the area could be obtained without creating additional discomfort. These patients were randomly assigned to the treatment group with P.R.G.F. or to the control group. The average age of the group of P.R.G.F. It was 41 years old (35 to 55 years old), 4 patients were male and 6 were female. The mean age in the control group was 42 years (38 to 54 years) of which 4 were males and 6 females.

In three additional patients (2 men and one woman), multiple extractions were planned in different oral areas. In each patient, P.R.G.F. in one area but not in another, assigning these areas randomly. In this way it was possible to have the best control group since both treatments were carried out in the same patient, with the same surgical procedure, identical icrobiological conditions and-by the same surgeon.

Each patient received an antibiotic treatment. Amoxicillin (1.5 g / day) was used. Displacement flaps were raised in all cases to allow adequate visibility and obtain closure for the first intention. Each post-extraction area was carefully curettage. In the ten patients of the experimental treatment, the defects were filled with P.R.G.F. In 5 of the cases, the plasma was mixed with autologous bone to prevent collapse of the flap. For the control sites, the protocol was the same but not filled with P.R.G.F. Membranes were not used in any case to prevent their barrier effect from interfering with the possible beneficial effects of P.R.G.F.

Biopsy technique The wounds were biopsied between weeks 10 and 1S depending on the availability of the patient. All were taken by an examiner who did not know the treatment that each site had received. The biopsies were taken with hollow trephine burs to a depth of 3 mm through the center of the wound. Bone biopsies were fixed with 10% buffered formalin in 5% formic acid for 48 hours and included in paraffil wax. Sections of a thickness of 5 microns were obtained from each biopsy and stained with hematoxylin and eosin. The stained sections were photographed under bright light field. All the biopsies were sent to a laboratory for analysis, without specifying which was the control group and which was the work group.

RESULTS Epithelization in all 10 patients treated with P.R.G.F. it was evaluated as very good or excellent, (much better than usual and comparatively better than the control zone). The regeneration of the treated areas was practically complete in 8 of the 10 cases. The degree of regeneration was evaluated with a periodontal probe and by comparison with the previous defects that had been photographed. Biopsies from these areas showed mature compact bone with well-organized trabeculae and normal morphology.

The other two cases treated with P.R.G.F. They showed a partial regeneration, presenting connective tissue with poorly organized trabeculae in the biopsies. Both patients, one male and one female, were smokers and had large defects of three alveolus walls.

There were significant differences in the degree of organization of the trabeculae between the biopsies taken at week 10 and those taken at week 16 and also depending on the size and shape of the defect. In patients with large defects treated with autologous grafts combined with P.R.G.F. To avoid the collapse of the flap, greater vestibular-lingual widths were obtained.

In all patients in the control group, a homogenous situation was found when reopening. All of them showed connective tissue filling most of the defect, in clear contrast with the cases treated with P.R.G.F. All biopsies of these patients showed connective tissue and connective tissue containing bone trabeculae. No bone-m-adura was found in any case. The epithelization range was considered normal, presenting significant differences with the cases treated with P.R.G.F.

In patients with defects in both hemiarchias, one treated with P.R.G.F. and the other in a conventional manner, the epithelization of the defects treated with P.R.G.F. It was much faster The biopsies showed a more mature bone with better organized trabeculae and greater bone regeneration in the defects treated with P.R.G.F.

The use of P.R.G.F. provides the conditions to obtain a faster and more effective bone regeneration. This gel P.R.G.F. It is easy to use but should be used without delay to preserve the activity of growth factors.

Although the optimal dosages are to be determined, the use of this technique does not introduce any risk to the patient, whose blood is used in a short period of time after extraction (30 minutes to 8 hours) and is not mixed with any other component. of human or animal origin. Currently around 250 patients have been treated with good clinical results.

It has been observed in practice that calcium sulphate sometimes has a relatively poor consistency when it is prepared for application with sterile biocompatible liquids, such as water, saline solutions and local anesthetic solutions, which could be an inconvenience for its handling during the treatment since it has a tendency to disintegrate and is very soluble.

In addition, it is rapidly diluted in the blood, so its efficiency in the regeneration of the bone tissue can be improved.

As a result of the experiments carried out in the laboratory, it has been noticed that the use can present in itself important advantages.

'First, tricalcium phosphate itself includes a greater amount of calcium.

Second, the behavior of tricalcium phosphate (putty, supersaturated solution), autologous bone mixed with P.R.G.F. (plasma rich in growth factors), P.R.P. (plasma rich in platelets), autologous bone P.R.G.F. more tricalcium phosphate, during the treatment in its diluted state is more homogeneous since it presents an adequate plasticity that makes it more manageable.

Third, the dilution in blood of tricalcium phosphate is more limited, less, than that of calcium sulfate, which generates its greatest use and its best barrier effect.

As indicated above, the material for filling the bone cavity can be essentially tricalcium phosphate mixed with plasma gel rich in growth factors or other combinations, while the material used as a barrier is tricalcium phosphate.

Within the invention as well, other combinations have been tried for the filler material, in combination with the tricalcium phosphate, such as: - Plasma rich in platelets - Autologous bone - Freeze-dried bone - Mixtures of the above In this way, the combination proposed with the present invention makes the work operations for the regeneration of the bone tissue more comfortable and easier to perform and, what is more important, the regeneration is carried out more quickly than with the methods and preparations known so far.

Claims (1)

1. CLAIMS 12 - Compound for the regeneration of the bone tissue and method of preparation, applicable in the technique of oral surgery, among others, in which a filling is made in the cavity to be regenerated with a graft material based on a mixture of autologous bone or other filling materials, whether or not a barrier material is present on this filling, characterized in that the composite The basic material used as a filling material is a plasma gel rich in growth factors (P.R.G.F.) obtained directly from the patient's own blood, in which this gel can occupy, at least partially, the regenerating cavity. Í5 2.2. - Compound for the regeneration of bone tissue and method of preparation, according to claim 12, characterized in that the plasma gel occupies only the entire cavity. 20 32-. - Compound for the regeneration of bone tissue and method of preparation, according to claim 13, characterized in that the plasma gel is mixed with autologous bone, alone, or in turn mixed with calcium sulfate. 25 42.. - Compound for the regeneration of the bone tissue and method of preparation, according to the claim, characterized in that the plasma gel is mixed with other regenerative, osteoconductive or osteoipductive materials, calcium sulfate, calcium carbonate, tricalcium phosphate, resorbable hydroxyapatite ••• etc. 52 - Method of preparation of the compound, characterized in that the following steps are followed, - extracting blood from the patient just before the start of surgery and prior to the administration of anesthesia, - the blood is extracted in citrated tubes at .10% with trisodium citrate, - centrifuge the tubes between 160 and 800 G for 6 to 7 minutes at room temperature, for the separation of the blood in the following constituents, red blood cells in the background, plasma rich in growth factors (PRGF) in the half and plasma poor in growth factors (PPGF) in the upper part, - collect the rich plasma (PRGF) and transfer it to Eppendorf tubes or glass test tubes, adding 10% calcium chloride and waiting for a time for gel formation. 6U- Method of preparation of the compound, according to claim 4, characterized in that, the collection of the product already centrifuged can include the uppermost part of the red blood cells. 72. - Method of preparation, according to 12 and 2 claims, characterized in that the blood extraction is in an amount of 10 to 50 ml. , using tu-bos from 5 to 10 ml. for centrifugation for 6 to 8 min. in which 1 ml will be housed in the Eppendorf tubes. of (P.R.G.F.), and once the calcium-chloride is added, the gel is formed between 2 to 20 minutes. 8i.- Method of preparation, according to Claim 4, characterized in that human thrombin is added together with calcium chloride. 92. - Preparation unit, according to 1 and 42 claims, characterized in that a unit for preparing the compound containing a centrifuge, pipettes for the separation of plasma fractions, and a system for blood extraction is constituted, as well as test tubes, Eppendorf tubes, tips for pipettes and a 37 degree heating block. IOS.- Method for the regeneration of bone tissue, based on a graft material that is housed in the bone cavity to be regenerated and another barrier material disposed above the previous one characterized by: - filling the bone cavity with a graft material comprising a mixture of plasma gel rich in growth factors and tricalcium phosphate of different granulometries, - providing a barrier on at least a portion of the graft material, the barrier material being tricalcium phosphate , mixed with PRGF, with factors obtained from PRGF, with physiological bone. 112. Method for the regeneration of bone tissue, according to claim 10, characterized in that the graft material is a mixture of platelet-rich plasma and tricalcium phosphate. 12i.- Method for the regeneration of bone tissue, according to the IOS claim, characterized in that the graft material is a mixture of autologous bone and tricalcium phosphate, with or without P.R.G.F. 13S.- Method for the regeneration of bone tissue, according to the IOS claim, characterized in that the graft material is a mixture of lyophilized bone and tricalcium phosphate. 14S.- Method for the regeneration of bone tissue according to IOS, lys, 12S and 13S claims, characterized in that the graft material is composed of tricalcium phosphate and a mixture of the rest of the compounds.